scholarly journals Arrestin-mediated Desensitization Enables Olfactory Discrimination in C. elegans

2021 ◽  
Author(s):  
Daniel M. Merritt ◽  
Isabel MacKay-Clackett ◽  
Sylvia M. T. Almeida ◽  
Celina Tran ◽  
Safa Ansar ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Olfactory System ◽  
Single Cells ◽  
Olfactory Receptors ◽  
Olfactory Discrimination ◽  
C Elegans ◽  
Olfactory Signal ◽  
Olfactory Stimuli ◽  
Nematode Worm ◽  
Behavioural Evidence

AbstractIn the mammalian olfactory system, crosstalk among diverse olfactory signals is minimized through labelled line coding: individual neurons express one or few olfactory receptors among those encoded in the genome. Labelled line coding allows for separation of stimuli during mammalian olfactory signal transduction, however, in the nematode worm Caenorhabditis elegans, 1,300 olfactory receptors are primarily expressed in only 32 neurons, precluding this strategy. Here we report genetic, pharmacological and behavioural evidence that β-arrestin-mediated desensitization of olfactory receptors, working downstream of the kinase GRK-1, enables discrimination between intra-neuronal olfactory stimuli, but that this discrimination relies on quantitative, rather than qualitative differences in signalling. Our findings suggest that C. elegans exploits β-arrestin desensitization to maximize responsiveness to novel odors, allowing for behaviourally appropriate responses to olfactory stimuli despite the large number of olfactory receptors signalling in single cells. This represents a fundamentally different solution to the problem of olfactory discrimination than that which evolved in mammals, allowing for economical use of an extremely limited number of sensory neurons.

scholarly journals Neuronal and non-neuronal signals regulate Caernorhabditis elegans avoidance of contaminated food

2018 ◽  
Vol 373 (1751) ◽  
pp. 20170255 ◽  
Author(s):  
Alexandra Anderson ◽  
Rachel McMullan
Keyword(s):  
Immune Response ◽  
Sensory Neurons ◽  
Cellular Immune Response ◽  
Risk Of Infection ◽  
Food Avoidance ◽  
C Elegans ◽  
Contaminated Food ◽  
Cellular Immune ◽  
Nematode Worm ◽  
Parasite Avoidance

One way in which animals minimize the risk of infection is to reduce their contact with contaminated food. Here, we establish a model of pathogen-contaminated food avoidance using the nematode worm Caernorhabditis elegans . We find that avoidance of pathogen-contaminated food protects C. elegans from the deleterious effects of infection and, using genetic approaches, demonstrate that multiple sensory neurons are required for this avoidance behaviour. In addition, our results reveal that the avoidance of contaminated food requires bacterial adherence to non-neuronal cells in the tail of C. elegans that are also required for the cellular immune response. Previous studies in C. elegans have contributed significantly to our understanding of molecular and cellular basis of host–pathogen interactions and our model provides a unique opportunity to gain basic insights into how animals avoid contaminated food. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours’.

scholarly journals The G-protein coupled receptor SRX-97 is required for concentration dependent sensing of Benzaldehyde in Caenorhabditis elegans

2020 ◽  
Author(s):  
Nagesh Y. Kadam ◽  
Sukanta Behera ◽  
Sandeep Kumar ◽  
Anindya Ghosh-Roy ◽  
Kavita Babu
Keyword(s):  
G Protein ◽  
Olfactory System ◽  
Olfactory Receptors ◽  
Guanine Nucleotide Binding Protein ◽  
C Elegans ◽  
Multiple Receptors ◽  
Genes Encoding ◽  
High Concentrations ◽  
Guanine Nucleotide Binding ◽  
G Protein Coupled

AbstractThe G-protein (heterotrimeric guanine nucleotide–binding protein)–coupled receptors in the olfactory system function to sense the surroundings and respond to various odorants. The genes encoding for the olfactory receptors in C. elegans are larger in number in comparison to those in mammals, suggesting complexity in the receptor– odorant relationships. Recent studies have shown that the same odorant in different concentration could act on multiple receptors in different neurons to induce attractive or repulsive responses. The ASH neuron is known to be responsible for responding to high concentrations of volatile odorants. Here we characterize a new GPCR, SRX-97. We found that the srx-97 promoter shows expression specifically in the head ASH and tail PHB chemosensory neurons of C. elegans. Further, the SRX-97 protein localizes to the ciliary ends of the ASH neurons. Analysis of CRISPR/based deletion mutants of the srx-97 gene suggest that this gene is involved in the recognition of high concentrations of benzaldehyde. This was further confirmed through rescue and neuronal ablation experiments. Our work gives insight into concentration dependent receptor function in the olfactory system and provides details of an additional molecule that could help the animal navigate its surroundings.

The glycomes of Caenorhabditis elegans and other model organisms

2002 ◽  
Vol 69 ◽  
pp. 117-134 ◽  
Author(s):  
Stuart M. Haslam ◽  
David Gems ◽  
Howard R. Morris ◽  
Anne Dell
Keyword(s):  
Caenorhabditis Elegans ◽  
Current Knowledge ◽  
Structural Data ◽  
Model Organisms ◽  
Entire Genome ◽  
C Elegans ◽  
The Face ◽  
Area Of Concern ◽  
Nematode Worm

There is no doubt that the immense amount of information that is being generated by the initial sequencing and secondary interrogation of various genomes will change the face of glycobiological research. However, a major area of concern is that detailed structural knowledge of the ultimate products of genes that are identified as being involved in glycoconjugate biosynthesis is still limited. This is illustrated clearly by the nematode worm Caenorhabditis elegans, which was the first multicellular organism to have its entire genome sequenced. To date, only limited structural data on the glycosylated molecules of this organism have been reported. Our laboratory is addressing this problem by performing detailed MS structural characterization of the N-linked glycans of C. elegans; high-mannose structures dominate, with only minor amounts of complex-type structures. Novel, highly fucosylated truncated structures are also present which are difucosylated on the proximal N-acetylglucosamine of the chitobiose core as well as containing unusual Fucα1–2Gal1–2Man as peripheral structures. The implications of these results in terms of the identification of ligands for genomically predicted lectins and potential glycosyltransferases are discussed in this chapter. Current knowledge on the glycomes of other model organisms such as Dictyostelium discoideum, Saccharomyces cerevisiae and Drosophila melanogaster is also discussed briefly.

scholarly journals The G Protein regulators EGL-10 and EAT-16, the Giα GOA-1 and the Gqα EGL-30 modulate the response of the C. elegans ASH polymodal nociceptive sensory neurons to repellents

BMC Biology ◽  
2010 ◽  
Vol 8 (1) ◽  
pp. 138 ◽  
Author(s):  
Giovanni Esposito ◽  
Maria R Amoroso ◽  
Carmela Bergamasco ◽  
Elia Di Schiavi ◽  
Paolo Bazzicalupo
Keyword(s):  
G Protein ◽  
Sensory Neurons ◽  
C Elegans

scholarly journals Steroid hormones sulfatase inactivation extends lifespan and ameliorates age-related diseases

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mercedes M. Pérez-Jiménez ◽  
José M. Monje-Moreno ◽  
Ana María Brokate-Llanos ◽  
Mónica Venegas-Calerón ◽  
Alicia Sánchez-García ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Caenorhabditis Elegans ◽  
Protein Aggregation ◽  
Steroid Hormones ◽  
Sensory Neurons ◽  
Environmental Cues ◽  
Steroid Sulfatase ◽  
Loss Of Function ◽  
C Elegans ◽  
Age Related

AbstractAging and fertility are two interconnected processes. From invertebrates to mammals, absence of the germline increases longevity. Here we show that loss of function of sul-2, the Caenorhabditis elegans steroid sulfatase (STS), raises the pool of sulfated steroid hormones, increases longevity and ameliorates protein aggregation diseases. This increased longevity requires factors involved in germline-mediated longevity (daf-16, daf-12, kri-1, tcer-1 and daf-36 genes) although sul-2 mutations do not affect fertility. Interestingly, sul-2 is only expressed in sensory neurons, suggesting a regulation of sulfated hormones state by environmental cues. Treatment with the specific STS inhibitor STX64, as well as with testosterone-derived sulfated hormones reproduces the longevity phenotype of sul-2 mutants. Remarkably, those treatments ameliorate protein aggregation diseases in C. elegans, and STX64 also Alzheimer’s disease in a mammalian model. These results open the possibility of reallocating steroid sulfatase inhibitors or derivates for the treatment of aging and aging related diseases.

scholarly journals Odor response adaptation in Drosophila—a continuous individualization process

2021 ◽  
Vol 383 (1) ◽  
pp. 143-148
Author(s):  
Shadi Jafari ◽  
Mattias Alenius
Keyword(s):  
Sensory Neurons ◽  
Olfactory System ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Olfactory Perception ◽  
Adaptation Mechanisms ◽  
Metabolic States ◽  
The Central Nervous System ◽  
Olfactory Adaptation ◽  
Central Adaptation

AbstractOlfactory perception is very individualized in humans and also in Drosophila. The process that individualize olfaction is adaptation that across multiple time scales and mechanisms shape perception and olfactory-guided behaviors. Olfactory adaptation occurs both in the central nervous system and in the periphery. Central adaptation occurs at the level of the circuits that process olfactory inputs from the periphery where it can integrate inputs from other senses, metabolic states, and stress. We will here focus on the periphery and how the fast, slow, and persistent (lifelong) adaptation mechanisms in the olfactory sensory neurons individualize the Drosophila olfactory system.

scholarly journals Region-specific amyloid-β accumulation in the olfactory system influences olfactory sensory neuronal dysfunction in 5xFAD mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Gowoon Son ◽  
Seung-Jun Yoo ◽  
Shinwoo Kang ◽  
Ameer Rasheed ◽  
Da Hae Jung ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Olfactory System ◽  
Amyloid Β ◽  
Olfactory Sensory Neurons ◽  
Basal Cells ◽  
Irreversible Damage ◽  
5Xfad Mouse ◽  
Peripheral Areas ◽  
5Xfad Mice

Abstract Background Hyposmia in Alzheimer’s disease (AD) is a typical early symptom according to numerous previous clinical studies. Although amyloid-β (Aβ), which is one of the toxic factors upregulated early in AD, has been identified in many studies, even in the peripheral areas of the olfactory system, the pathology involving olfactory sensory neurons (OSNs) remains poorly understood. Methods Here, we focused on peripheral olfactory sensory neurons (OSNs) and delved deeper into the direct relationship between pathophysiological and behavioral results using odorants. We also confirmed histologically the pathological changes in 3-month-old 5xFAD mouse models, which recapitulates AD pathology. We introduced a numeric scale histologically to compare physiological phenomenon and local tissue lesions regardless of the anatomical plane. Results We observed the odorant group that the 5xFAD mice showed reduced responses to odorants. These also did not physiologically activate OSNs that propagate their axons to the ventral olfactory bulb. Interestingly, the amount of accumulated amyloid-β (Aβ) was high in the OSNs located in the olfactory epithelial ectoturbinate and the ventral olfactory bulb glomeruli. We also observed irreversible damage to the ectoturbinate of the olfactory epithelium by measuring the impaired neuronal turnover ratio from the basal cells to the matured OSNs. Conclusions Our results showed that partial and asymmetrical accumulation of Aβ coincided with physiologically and structurally damaged areas in the peripheral olfactory system, which evoked hyporeactivity to some odorants. Taken together, partial olfactory dysfunction closely associated with peripheral OSN’s loss could be a leading cause of AD-related hyposmia, a characteristic of early AD.

scholarly journals Polymodal Functionality of C. elegans OLL Neurons in Mechanosensation and Thermosensation

2021 ◽  
Author(s):  
Yuedan Fan ◽  
Wenjuan Zou ◽  
Jia Liu ◽  
Umar Al-Sheikh ◽  
Hankui Cheng ◽  
...  
Keyword(s):  
Glutamate Receptor ◽  
Sensory Neurons ◽  
Molecular Mechanisms ◽  
Temperature Sensitive ◽  
Cold Sensation ◽  
Cold Response ◽  
C Elegans ◽  
Sensory Modalities ◽  
A Cell ◽  
Bona Fide

AbstractSensory modalities are important for survival but the molecular mechanisms remain challenging due to the polymodal functionality of sensory neurons. Here, we report the C. elegans outer labial lateral (OLL) sensilla sensory neurons respond to touch and cold. Mechanosensation of OLL neurons resulted in cell-autonomous mechanically-evoked Ca2+ transients and rapidly-adapting mechanoreceptor currents with a very short latency. Mechanotransduction of OLL neurons might be carried by a novel Na+ conductance channel, which is insensitive to amiloride. The bona fide mechano-gated Na+-selective degenerin/epithelial Na+ channels, TRP-4, TMC, and Piezo proteins are not involved in this mechanosensation. Interestingly, OLL neurons also mediated cold but not warm responses in a cell-autonomous manner. We further showed that the cold response of OLL neurons is not mediated by the cold receptor TRPA-1 or the temperature-sensitive glutamate receptor GLR-3. Thus, we propose the polymodal functionality of OLL neurons in mechanosensation and cold sensation.

Olfactory Stimuli and Oviposition in the Blowfly, Phormia Regina Meigen

1962 ◽  
Vol 39 (4) ◽  
pp. 603-615
Author(s):  
D. I. WALLIS
Keyword(s):  
Olfactory Receptors ◽  
Phormia Regina ◽  
Minor Role ◽  
Egg Distribution ◽  
Tactile Stimuli ◽  
Olfactory Stimuli ◽  
Behavioural Experiments ◽  
A Minor ◽  
Sensory Mechanisms

1. The work described attempts to elucidate the sensory mechanisms involved in the act of oviposition. 2. A brief account of the morphology of the ovipositor and the distribution of the various sensilla on it is given. 3. Behavioural experiments have shown unequivocally that receptors on the anal leaflets of the ovipositor are olfactory and can mediate oviposition. Flies are able to discriminate when antennal, palp and labellar receptors are blocked, but not when the ovipositor pegs are waxed over as well. A method for waxing the latter is described. 4. Sensilla on the antennae, labellum and ovipositor perceive the olfactory stimuli which are important in inducing oviposition. Possibly there are olfactory receptors at other sites which mediate other types of behaviour. 5. Tactile stimuli perceived mainly through sensilla on the ovipositor can play an important role in egg distribution and a minor role, possibly, in inducing oviposition. 6. All the evidence suggests the pegs are the olfactory receptors on the ovipositor which mediate oviposition. 7. A summary of factors known or suspected to influence oviposition is given.

Cranial Nerves I and II

2021 ◽  
pp. 115-119
Author(s):  
Kelly D. Flemming ◽  
Eduardo E. Benarroch
Keyword(s):  
Optic Nerve ◽  
Sensory Neurons ◽  
Chloride Channels ◽  
Calcium Influx ◽  
Cranial Nerves ◽  
Sensory Information ◽  
Olfactory Receptors ◽  
Olfactory Nerve ◽  
Afferent Nerve ◽  
Gated Channel

Cranial nerves I (olfactory nerve) and II (optic nerve) are supratentorial, paired cranial nerves. This chapter provides an overview of their anatomy. Cranial nerve I is a special visceral afferent nerve carrying sensory information about odors. Olfactory receptors lie in the nasal cavity. Odorants activate receptors within the cilia of olfactory sensory neurons and trigger the opening of a cyclic nucleotide–gated channel. This channel allows a calcium influx and the opening of calcium-activated chloride channels. Depolarization then occurs.

Sign in / Sign up

Export Citation Format

Share Document